Hi Folks my Integrated Valve amp has packed up and won't be fixed till post Xmas. With 400volts inside diagnosis is best left to a pro not an amateur like me.
So I've ordered an ACA to build that I should be able to drive from a Cambridge DAC magic. The DAC has RCA outputs and a Volume pot that can be used or bypassed.
The big problem I have is that even the ACA may be too much power for my 106DB per watt horn speakers. I've got an Alps blue volume pot lying around - any harm in wiring it into the ACA after the RCA connectors to attenuate the volume if needed. Is the front panel pre-drilled for the power switch - volume pot just there might be perfect. Fingers crossed it arrives soon need some music through my speakers not just headphones soon. FEDEX specified for everything
So I've ordered an ACA to build that I should be able to drive from a Cambridge DAC magic. The DAC has RCA outputs and a Volume pot that can be used or bypassed.
The big problem I have is that even the ACA may be too much power for my 106DB per watt horn speakers. I've got an Alps blue volume pot lying around - any harm in wiring it into the ACA after the RCA connectors to attenuate the volume if needed. Is the front panel pre-drilled for the power switch - volume pot just there might be perfect. Fingers crossed it arrives soon need some music through my speakers not just headphones soon. FEDEX specified for everything
... So I've ordered an ACA to build that I should be able to drive from a Cambridge DAC magic. The DAC has RCA outputs and a Volume pot that can be used or bypassed.
The big problem I have is that even the ACA may be too much power for my 106DB per watt horn speakers. I've got an Alps blue volume pot lying around - any harm in wiring it into the ACA after the RCA connectors to attenuate the volume if needed. Is the front panel pre-drilled for the power switch - volume pot just there might be perfect. Fingers crossed it arrives soon need some music through my speakers not just headphones soon. FEDEX specified for everything
Hi Steve,
Long answer:-
1st. I understand you can order the ACA chassis with or without the front switch hole? Did you specify one in your order?
2nd. The front panel is 10mm thick (and the switch hole if it has one, 20mm in diameter) so normal pots are a challenge to fit.
3rd. Unlikely the ACA will be too powerful! It will actually depend on the voltage output of the DAC Magic. (2.1 volts via RCAs I see.) It's that that limits the volume you will be able to get. (The ACA has a 3.3 times voltage gain.)
Shorter answer, just use the volume control on the DAC and enjoy! Alan
We'll see with just 9 watts available on my Valve amp I still had to put resistors on the volume pot to enable more than a quarter turn on the volume pot. It'll be fun so see how this amp sounds. https://i.pinimg.com/originals/07/7a/f2/077af2f37df4803397051a7f11160b6d.jpg
Probably going to sell my 3 brand new ACAs
I just built 3 v1.6 Batch 3 ACAs to power my 3.1 theater system. They each sound amazing on a pair of small bookshelf speakers I have (especially when wired up as mono blocks). However, I was hoping as mono blocks they'd be powerful enough for my custom-built L-C-R home theater speakers but unfortunately not. Since they were custom builds I have no idea what their efficiency rating is (or even rated power... probably north of 200 Watts).
So... I think I am just going to turn around and sell these. Does anyone have any suggestions on what a fair price to sell 3 completed v1.6 (batch 3) ACAs that are brand new (finished one last week, and finished the other two last night and have been burning in that latest 2 for a couple of hours this morning with some Nick Drake and Mark Knopfler)!?
They each cost me roughly $350 + $10 supplies (Cardas solder and heat shrink tubing). The 3 together probably took me ~20 hours to build. So I was thinking $460 each would be a steal for someone and compensate my build time somewhat.
I am in Saint Petersburg, FL if anyone local wants to check them out. I also can upload a bunch of pictures of them if anyone is interested here. I guess if no one is interested I will have a friend throw them up on Ebay (but probably put up a post here too).
I just built 3 v1.6 Batch 3 ACAs to power my 3.1 theater system. They each sound amazing on a pair of small bookshelf speakers I have (especially when wired up as mono blocks). However, I was hoping as mono blocks they'd be powerful enough for my custom-built L-C-R home theater speakers but unfortunately not. Since they were custom builds I have no idea what their efficiency rating is (or even rated power... probably north of 200 Watts).
So... I think I am just going to turn around and sell these. Does anyone have any suggestions on what a fair price to sell 3 completed v1.6 (batch 3) ACAs that are brand new (finished one last week, and finished the other two last night and have been burning in that latest 2 for a couple of hours this morning with some Nick Drake and Mark Knopfler)!?
They each cost me roughly $350 + $10 supplies (Cardas solder and heat shrink tubing). The 3 together probably took me ~20 hours to build. So I was thinking $460 each would be a steal for someone and compensate my build time somewhat.
I am in Saint Petersburg, FL if anyone local wants to check them out. I also can upload a bunch of pictures of them if anyone is interested here. I guess if no one is interested I will have a friend throw them up on Ebay (but probably put up a post here too).
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IMO almost the whole point of a kit build is the fun of assembling it yourself. So by building the kits you've removed some of the value. I personally wouldn't pay more for an assembled kit than the cost of it's parts and shipping. I'd want a reduction in price if anything. Aim to recover your purchase costs but not your labour.
Better still build some single driver high efficiency speakers and keep the amps.
Better still build some single driver high efficiency speakers and keep the amps.
I agree with Steve luck . Fog Audio I also believe in high-efficiency speaker if you already went through all the trouble of building those amplifier and the trouble should be changed to joy because they absolutely can produce Thunderderious volume of sound out of the proper speaker. If you do decide to build a different amplifier for the speaker if you have already built then First you need to do the research into the speakers you have built before taking a blind shot in the dark at what is actually the proper amplifier for your particular speakers. Sounds like you have some in impedance matching and efficiency matching to do before guessing on which amplifier is best for your individual needs. For example in your situation ( you would not take a camp camp amp and hook it up to a pair of 15 inch sub that only had 80% efficiency and required between 200 and 600 W to drive them.) and then turn around and say there’s something wrong with these amplifiers, they don’t do the job?.
Well, yeah mea culpa for not knowing the efficiency rating of my custom speakers. Unfortunately, I don't have the measuring equipment to perform that measurement myself and the specifics of them are not available from the boutique brand that sold me the parts as a kit. The builder no longer makes or provides specs on this speaker either.
I am fairly certain they are 8ohm speakers (dual 6" mid-woofers and RAAL 70-10 ribbons) and didn't think they'd be too demanding for a 15 Watt mono block but I guess I was wrong. I love the sound of my speakers, they are absolutely amazing and I also really like the sound of these mono blocks, but unfortunately for me they are not compatible.
Steve Luck, I do agree with you that a lot of the fun is building them. However, I am sure that many out there may not have the expertise or equipment to perform such a build (OTOH, those probably aren't the type of folks lurking on diyaudio, LOL). I ended up buying a new multimeter, third-hand station, Haako soldering station, and other equipment to make this build. I spent over $200 in equipment dedicated for this project which I of course I don't expect to recoup and of course will be really useful for future projects. Anyway, just my opinion, but I would certainly disagree with you that 20 hours of my time diminishes the value of these ACAs.
R/,
Ryan
Nelson Pass THANK YOU, I just got my ACA Ver.1.6 finished. I have had the privilege of listening to many high end amps, PASS amps included. I could never afford any of them as a retired USAF NCO. These ACA's are so close to the big boys is amazing. I made a couple of errors on output connections but found the problem and corrected it. Getting old. I soldered it with some 4% silver solder I had laying around. They absolutely blow away my home built KT88/6550 SE amp, Probably the output transformers. My system isn't the best but it's what I can afford. Sony SCD-CE595 SACD player, Carver C-1 Preamp I bought new, NAD Tuner I have a low power FM radio station 89.5Mhz, about 1 mile range, and Klipsch Cornwalls Crites updated. I want to say THANK YOU to all involved in this kit to production. WOW I just can't believe how great this amp sounds, deep powerful bass, liquid mids voices so clear, crisp high end but not bright and DEAD quiet with the supplied power supply. Notes.. It took 4 times to get the bias dead on 12.00 volts. Yes I'm a perfectionist. If you increase the voltage it overshoots and then under shoots and finally settles in about 30 to 45 seconds after adjustment. reverse if you reduce voltage. Tiny movements. One question--- My amp runs at 53C to 55C after one hour and stays there 12 hours ir's the same. Is this OK? I also get a very slight ramp up noise during power on, Probably capacitor charge and the efficacy of my speakers 102Db. Once again THANKS to all involved in this project.
First, well done glad you like it.
Second, yes they run Hot (each channel dissipates 36 Watts so 72 in total.)
So 55 degrees C is fine. (If you can put your hand on it for more than 10 seconds it's fine!) The start up fizz (fart) is normal, just the big output capacitor, C1, charging up.
Enjoy, Alan
Completed mine today - extraordinary amp when put on sensitive speakers! Thought i had parts over - but looks like nuts and spring washers are for those not screwing the transistors into the threaded heat sinks that you get if you buy the case too.
LED definitely too bright - anyone got any resistor value ideas? I've got a few lying around.
Many thanks to all that put this project together build photos etc.
Matching phono stage (MM) and passive pre-amp would be cool.
LED definitely too bright - anyone got any resistor value ideas? I've got a few lying around.
Many thanks to all that put this project together build photos etc.
Matching phono stage (MM) and passive pre-amp would be cool.
On home built gear that isn't necessarily put together from a kit it's common to ask the cost of the parts. It might be the place to start for your ACA's.
There's a gentleman that regularly attends the Lone Star Audio Fest who would bring a new set of speakers he had built every year. He did this year after year. When asked what he does with all the speakers he said he (and his friends) would enjoy them for a bit then he'd put them on the market for whatever the parts costs had been. The cost of the woofers, tweeters, wire, caps, wood, etc. would be added up and that would be their selling price. Some young audiophile would get a beautifully built pair of speakers for the cost of the parts.
Then he'd build a different pair of speakers and repeat the cycle. Over time he and his buddies had the chance to listen to an awful lot of speakers. It seemed like a pretty nice way to enjoy this hobby.
Congrats on finishing the project!
Just a minor note, ideally you should put a spring washer between the bolt and the washer that holds the MOSFET in place. In that way you even out any misalignments and allow for 'ideal' area contact.
It's probably not a huge deal, but it would take little effort to add them one by one (so you don't risk pivoting the PCB). I'd do it if you havent yet done so.
I finally decided not to change led resistors, as my tests suggested that there is a very narrow area of brightness change, and then you are quickly at full led brightness. So I finally put a translucent blue hard plastic between the led and chassis, and that nicely dimmed the led while also preventing the change between side views and straight forward.
I'm happy with that fix.
Best regards,
Rafa.
Did the spring washers between set screw head and flat washer during the build. I think the spares must be intended for those bolting right through a heatsink.�� Re the LED I like your thinking, I have a lot of Perspex and brother in law with a 3D printer maybe make something to fit in the holes and light up the case inside at the same time.
I went to qrz, nice setup you have Jim. Old Heathkit fan here. My favorite novice rig was the hot water 16, then later on a pair of SB twins 301/401. Currently have an Elecraft KX3 driving a SB-1000 through a Heath SA-2060a tuner into some dipoles and a hexbeam. Mighty nice antenna setup you have.
David
David
Bright LEDs
Agree totally on the bright LEDs. I originally used the blue ones and they were way too bright. Switched to the red ones with a 72K ohm resistor and that toned them down enough. I’d like to see some resistors included in the kit for this purpose. I can’t imagine anyone wants LEDs so bright you could use them to land aircraft.
Agree totally on the bright LEDs. I originally used the blue ones and they were way too bright. Switched to the red ones with a 72K ohm resistor and that toned them down enough. I’d like to see some resistors included in the kit for this purpose. I can’t imagine anyone wants LEDs so bright you could use them to land aircraft.
v1.6 can handle Apogee Centaurs
I had to try it: Primare i22 used as pre-amp, ACA v1.6 as power amp and Apogee Centaurs as speakers.
It really sounds beautiful! The Centaurs are hybrid ribbon speakers with a sensitivity of 84dB at 3 meters, impedance is 5 Ohms nominal and 3 Ohms minimum.
I had to try it: Primare i22 used as pre-amp, ACA v1.6 as power amp and Apogee Centaurs as speakers.
It really sounds beautiful! The Centaurs are hybrid ribbon speakers with a sensitivity of 84dB at 3 meters, impedance is 5 Ohms nominal and 3 Ohms minimum.
Attachments
After laying out my resistors alongside the BOM I almost put R13 where R14 should go because they go R11 R12 R14 across the board. That would be an easy mistake.
https://d17kynu4zpq5hy.cloudfront.net/igi/diyaudio/mlJULs3AJ6mME4ed.huge
Keep checking the build guide is pretty good.